Refrigerating apparatus with means for indicating the quantity of solid refrigerant therein



Aug. 1 7, 1948. c. E. HEILIG, JR

REFRIGERATING APPARATUS WITH MEANS FOR INDICATING THE QUANTITY OF SOLID REFRIGERANT THEREIN Filed March 6, 1946 v INVEN TOR. mamas E. Hf/L/G- If? HGENT' v Q Patented Aug. 17 1948 BE FRIGERATING APPARATUS WITH MEANS FOR INDICATING THE QUANTITY OF SOLID REFRIGERAN'I. THEREIN Charles E. Heilig, Jr., Upper Darby, Pa, assignor,

by mesne assignments, to Philco Corporation,

Philadelphia, 2a., a corporation of Pennsylunis Application March 6, 1946, Serial No. 652,354

8 Clllml. (Cl. 62-49) This invention is concerned with heat exchange apparatus for use in refrigerating systems.

More especially, the invention relates to systems of the type which utilize latent heat of fusion in the provisional refrigeration, and to apparatus for indicating the quantity of refrigerating effect available in such systems.

Refrigerators have been devised, which employ, as their cooling medium, a vessel containing a suitable fluid congealable at some predetermined relatively low temperature, and characterized by a latent heat of fusion which is sufficiently high to provide substantial refrigerating effect at the region of the melting point. When the refrigerating effect of the congealed fluid is substantially exhausted, the vessel is removed and the fluid refrozen, by the use of any convenlent apparatus.

It is a primary object of the present invention to provide, in systems of the aforesaid type, an indication ofv the amount of refrigerating effect available.

More particularly, the invention contemplates the provision of continuous visual indication of the available refrigeration, and, preferably, in terms of hours of refrigerating effect. To this end, indicating apparatus is provided which is.

Referring to the drawings, there is shown in Figure l and designated generally by the reference character III, a vertical or top-access refrigerator having a door or lid'il which is shown in open position and supports upon its lower surface the refrigerant-containing vessel II. In use, as will be appreciated, the vessel i2 extends downwardly into the space to be refrigerated and is removablyassociated with the lid il by any convenient mounting means (not illustrated). This vessel may be fabricated of sheet metal or other fluid-tight material having the desired high heat transfer characteristics.

While any of a. number of congealable substances might be used within the vessel l2, such as a solution of calcium chloride and water, and others, I prefer to employ the eutectic solution of water and sodium chloride, which has a melting point at a temperature suiliciently low for most refrigeration pu p ses. mal expansion during freezing, the quantity of solution is such as to provide free space within the vessel to permit such expansion, it being home in mind that a solution of the type chosen will expand upon freezing,

As shown at iii in Figure 2, whichflgure illustrates the forward face of the container as it would appear in the horizontal position assumed during use, the liquid level is spaced suiiiciently Figure 3 is a view, partly in section and partly of general utility where such heat exchange apparatus is desired.

from pressure sensitive bulb ii (to be later described) to ensure that the frozen solution will not contact or interfere with the operation of the indicating apparatus. Further to illustrate the freedom which is provided for expansion, there is shown, at lie in Figure 3, the level which the unfrozen solution may preferably assume when the vessel is so arranged as to present the face of the indicator upwardly. Such orientation of the container may be desirable during freezing of the solution, preparatory to its use as a refrigerant. As will be clear, when the apparatus is in use, the latent heat of fusion required to melt the frozen solution within container I2 is drawn from the To accommodate nor- -container. During operation,

ating 'efi'ect availableby the utilization of any changes in the physical state of the refrigerating substance'which may occur during the melting thereof, there is illustrated and preferably employed a gauge which is responsive to pressure changes occurring at constant volume, within the above the frozcnsubstance is occupied either by air or vapor, and it will be appreciated that the pressure in thi space will be at a maximum when the substance is completely frozen, and will vary with the melting of the substance and consequent change of volume thereof. It will be understood, of course, that if desired the maximum pressure may be caused to occur when the substance is completely melted, by the choiceof a freezable substance characterized by contraction upon freezing. 1

The instrument I! may be of the type known as a Bourdon" gauge, having therein a-coiled tube of elliptical cross-section, one end of which tube extends within the container (as shown at I! in Figure 2). in communication with the space above the refrigerating substance. -As abovementioned, a pressure responsive member H, of rubber or the like, is carried by the open end of the tube portion i1, said member serving to vary the pressure within the gauge while still preventing entrance of unfrozen solution. The auge is provided with an indicating needle l8, suitably coupled to the pressure-responsive coil aforesaid, said needle being adapted to move in a counterclockwise sense in response to diminutions in the pressure within the vessel or container l2. Since this type of pressure gauge is well known, further detailed description is confined to its novel calibration, peculiar to this invention.

In accordance with a feature of the invention, the gauge includes a dial calibrated in hours of refrigerating sheet as a function of both ambient temperature, and the quantity of solid solution in terms of percentage. An example will best illustrate the further construction as well as the operation of the apparatus.

Assuming an initial condition in which the refrigerating substance is completely frozen, the gauge is so designed that the needle will lie in the central, vertical position (as the gauge appearsin Figure 2) in which position it indicates that 100% of the solution is in the solid state. Now, as refrigeration occurs, and the solution begins to melt, the pressure upon the member M will be reduced, and the gauge moves in the counterclockwise direction, toward the position shown in Figure 2. To determine the hours of refrigerating efi'ect remaining, the user, knowing the ambient temperature, refers to the gauge and selects that scale corresponding to the prevailing ambient temperature. In the example illustrated, assuming an ambient temperature of 60 F., the remaining refrigerating effect would amount to 7 hours, and such is indicated by that portion of the needle cooperating with the outermost annular scale, Similarly, if a subsequent observation, taken at an ambient temperature of 80-F., indicates that 50% of the solution remains in the solidstate, the operator may readily determine that 3 hours of refrigeration remain.

The calibration points illustrated are shown merely by way of example, it being understood that, in practice, the gauge would be suitably cali brated in accordance with the particular use to which the apparatus is to be put. The size and nature of the cabinet, the quantity and type of solution employed, and the nature of the average the free space V heat load, all represent factors which would be taken into account in determining the gauge calibration required for any particular system.

From the foregoing, it will be recognized that the present invention greatly increases the utility of refrigeration systems of the type concerned, and avoids the spoilage of frozen foods and the like, by providing the user with a. positive indication of the amount of refrigerating effect available, before the solution need :be refrozen. While the invention is of broad applicability. it is particularly useful in the provision of auxiliary or stand by refrigeration, the use of containers in accordance with the invention making it possible safely and stably to maintain a desired refrigerating temperature.

I claim:

1. Heat exchange apparatus for use in refrigerating systems, said apparatus comprising a vessel containing a normally fluid substance congealable at a predetermined relatively low temperature and characterized by a latent heat of fusion sufllcientlyhigh to provide substantial refrigerating effect during the; melting thereof, said substance being at least partially congealed during normal operation of the apparatus, and means responsive to-variations in the quantity of substance congealed to indicate the hours of refrigerating effect available.

. 2. Heat exchange apparatus for use in refrigerating systems, said apparatus comprising a vessel containing a normally fluid substance congealable at a predetermined relatively low temperature and characterized by a latent heat of fusion sufficiently high to provide substantial refrigerating effect during the melting thereof, said substance being at least partially congealed during normal operation of the apparatus, the pressure within said vessel being variable in accordance with the quantity of substance congealed, and means responsive to such pressure variations to indicate the amount 01' refrigerating effect available.

3. Heat exchange apparatus for use in refrigerating systems, said apparatus comprising a vessel containing a normally fluid substance congealable at a predetermined relatively low temperature and characterized by a latent heat of fusion sumciently high to provide substantial refrigerating effect during the melting thereof, said substance being at least partially congealed during normal operation of the apparatus, and means responsive to variations in the physical state of said substance to indicate the amount of refrigerating effect available, said means including indicia calibrated as a function of both ambient temperature and quantity of substance congealed.

4. Heat exchange apparatus'for use in refrigerating systems, said apparatus comprising a vessel containing a normally fluid substance congealable at a predetermined relatively low temperature and characterized by a latent heat of fusion sufllciently high to provide substantial refrigerating effect during the melting thereof, said substance being at least partially congealed during normal operation of the apparatus, the pressure within said vessel being variable in accordance with the quantity of substance congealed, and a gauge carried by said-vessel and responsive to pressure variations therein, said gauge including means calibrated'as a function of both ambient temperature and quantity of substance congealed and indicative of the amount of refrigerating effect currently available.

5. Heat exchange apparatus for use in refrigerating systems, said apparatus comprising a vessel 5 containing a normally fluid substance congealable at a predetermined relatively low temperature and characterized by a latent heat of fusion sufliciently high to provide substantial refrigerating effect during the melting thereof, said Substance being at least partially congealed during normal operation of the apparatus, the pressure within said vessel being variable in accordance with the quantity of substance congealed, and a gauge carried by said vessel and responsive to pressure 10 variations therein, said gauge including indicla calibrated in terms of the currently available amount 01 refrigerating effect as determined by the pressure within said vessel and hence the quantity of substance congealed, said indicia including a plurality of scales each applicable under a diflerent condition of ambient temperature.

6. Heat exchange apparatus for use in refrigeratin'g systems, said apparatus comprising a'vessel containing a normally fluid substance congealable at 'a predetermined relatively low temperature and characterized by a latent heat of fusion sufllciently high to provide substantial refrigeratinp eflect during the melting thereof, said substance said vessel.

cHanL s E. rmnm, Ja'. REFERENCES crrEn The following references are of recordIin-the file of this patent:

UNITED STATEBPATENTS Number Name Date 942,286 Sansbury et al. Dec. 7, 1909 1,072,453

Hausner et al. Sept. 9, 1943 

